libproc_macro: Drop function shall take a mutable

The rust API requires a mut reference, hence having a mutable pointer
seems to match better. Furthermore the implementation is now modifying
the struct in order to set the size to 0 instead of simply freeing the
data, this will allow us to easily identify mistaken manual call to this
function.
ChangeLog:

	* libgrust/libproc_macro/rust/bridge/literal.rs: Make the
	pointer mutable.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/libgrust/libproc_macro/rust/bridge/literal.rs b/libgrust/libproc_macro/rust/bridge/literal.rs
index 080cc1b..740ed1f 100644
--- a/libgrust/libproc_macro/rust/bridge/literal.rs
+++ b/libgrust/libproc_macro/rust/bridge/literal.rs
@@ -6,7 +6,7 @@ use std::str::FromStr;
 use LexError;
 
 extern "C" {
-    fn Literal__drop(literal: *const Literal);
+    fn Literal__drop(literal: *mut Literal);
     fn Literal__string(str: *const c_uchar, len: u64) -> Literal;
     fn Literal__byte_string(bytes: *const u8, len: u64) -> Literal;
     fn Literal__from_string(str: *const c_uchar, len: u64, lit: *mut Literal) -> bool;
@@ -230,7 +230,7 @@ impl Drop for Literal {
     fn drop(&mut self) {
         match self {
             Literal::String { .. } | Literal::ByteString { .. } => unsafe {
-                Literal__drop(self as *const Literal)
+                Literal__drop(self as *mut Literal)
             },
             _ => (),
         }